Fix logger and trying to fix codeclimate

Fix logger for assets pipeline:

```bash
** [out :: xxx] W, [2013-11-23T14:13:18.572971 #11230]  WARN -- : Webp convertion error of image active_admin/admin_notes_icon-27fadf658c2613c80e13bd19fa58912f.png.webp. Error info: Cannot read input picture file
** [out :: xxx] I, [2013-11-23T14:13:18.573974 #11230]  INFO -- : Writing /var/www/falcon-web/releases/20131123141135/public/assets/active_admin/admin_notes_icon-27fadf658c2613c80e13bd19fa58912f.png
```

 and trying to fix codeclimate: https://codeclimate.com/github/kavu/sprockets-webp/Sprockets::WebP::Converter?from_sha=4aa136f2&to_sha=15755e9a